Low-water alarm for steam-boilers.



BATENTED JAN. so, 190e. D.

Low. WATER ALARM B011 STEAM BOILERS.

APPLICATION FILED NOV 2 SHEETS-SHEET l.

PATBNTBD JAN. so, 1906. o. G. GILDARD. Low WATER ALARM PoR STEAMBOILBRS.

APPLICATION PIIAED NOV. 10, 1904.

No. 811,213.v

2 SHEETS-SHEET 2.

UNITED "STATES PATENT oIFIon.

)HRISTOPHER G. GILDARD, OF SWANSEA, MASSAHUSETTS.

LOW-WATER LARNI FOR STEAlVl-BOILERS.

To .all whom it man concern:

Be it known that I, CHRISTOPHER G. GIL- DARD, a citizen of the UnitedStates,.residing at Swansea, in the county' of Bristol and State ofMassachusetts, have invented aLow-Water Alarm for Steam-Boilers, ofwhichthe following is a specification.

My invention relates to improvements in low-water alarms forsteam-boilers.

The invention has particular reference to an attachment to that class ofboilers and their auxiliaries as employed in steam automobiles whereinis used a fusible-plug attachment and in which, when the water reaches acertain point, the fusible plug, being exposed to the heat of theburner. and no longer protected by water, quickly melts and is blown outby the pressure of steam contained in the boiler. One of thedisadvantages of this class of automobiles results from the fact thatwhen the water becomes low and the plug is melted and discharged thesteam4 escapes and it becomes necessary before proceeding for theoperator to pump up to the proper level the water in the boiler by meansof an auxiliary hand-pump and raise the steam to its normal pressure, orthereabout, such operation being preceded, of course, by the removal ofthe tube or pipe em loyed to carry the plug and the renewal of 151e plugin said tube and the insertion of the latter in position, or else theinsertion of substitute tube or pipe already plugged for the occasion.

The objects of my invention are, first, to

save the steam-pressure, or, in other wor'ds, to prevent the same frombeing reduced or lowered by reason of the blowing out ofthe plug;second, to sound an audible alarm as a warning to the operator that theplug has been blown and that the water is therefore dangerously low,and, third, to provide for an immediate and 'automatic cutting off ofthe gasolene-supkply, whereby even thou h the operator faile to note thealarm yet t e boiler cannot be burned or scorched.

Other objects and advantages of the invention will hereinafter appear,and the novel features thereof will be particularly pointed out in theappended claims.

Referring to the drawings, Figure 1 is a view showing my improvedsystem, the fusible plug being in position. Fig. 2 is a similar viewshowing the same parts as they will appear after the fusible plug hasbeen melted and blown out, and therefore the water'below the normalwater-line. Fig. 3 is af-'v'ertieal A Specification of Letters Patent.

. Application filed November 10, 1904. Serial No. 232.164.

Patented J an. 30, 1906.

longitudinal sectional view through the fusible-plug attachmenthereinafter referred to. Fig. 4 is a transverse sectional view taken onthe line 4 4 of Fig. 3. Fig. 5 is adetail perspective of a removablethreaded plug for closing the lowerend of the sliding sleeve.

Like numerals of reference indicate like I vaporizer 1 op osite thevaporizing-nozzle 2 and has locate at some point most convenient acut-olf 5, which is normally open.

6 designates the tube or pipe, which leads from an opening in the underside ofY the usual fire-tube boiler and projects to a point near anopening in the boiler-casing. -Threaded removably within the outer endof the tube 6 is the fusible-plug tube or p ipe 7, the fusible-plugbeing indicated, asat 8, by dotted lines. ,j

The tube 7 has heretofore been left, as above described, with the outerend extending beyond the burner-casing, where it may be gripped by meansof gas-pliers or other tool for the purpose of unscrewing when thefusible plug shall have been blown out. In the present instance,however, I thread upon the outer end of the tube 8 an elbow 9,connecting it to a tube 10, which may have located therein a cut-0H orvalve 11,l provided at its outer end with an angular stud or stem 12.Upon this stud or stemv 12 I may removably mount a bell-crank 13, usinga cotter-pin- 14 or other fasteningdevice for temporarily securing saidbell-crank in position. The lower end of thetubeor eipelnllay be formedwith a disk-like head 15, (see Fl`g."3,`;"'

and mounted on said tube or pipe so as to slide is a cylindrical sleeve16, the upper end of which fits closely about the tube or pipe 10, andthe lower end of which is open and internally threaded. The internaldiameter of the sleeve 16 substantially agrees with the diameter lof thedisk-like head 15, and between the latter and the upper end of thesleeve a coiled spring 17 of the compression type is located, thetendency of which spring is to normally elevate the sleeve against awasher 18, likewise mounted on the tube or pipe 10.

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the sleeve 16 is a cap or plug 19, (see Figs. 3 and 5,) the same beingexternally threaded, as shown, to fit the lower end of the sleeve andprovided on its under side with a squared boss 20 to receive a wrenchand by means of which it may be removed or set in position. This cap isfurther formed with a central perforation 21, and mounted for receptionthereon is a stem 22, which extends above and below the cap. At itsupper end the stem carries a head 23, preferably of angular shape, so asto leave a clearance between the sides of said head and the wall of thesleeve 16. A coiled compression-spring 24 is interposed between thishead and theupper side of the cap 19 and serves to normally elevate thehead 23. The latter has located upon its upper side a stud 25, whichcoming against the under side of the disk-like head 15 spaces the twoheads apart and prevents close contact. The stein 22 has located in itslower end an ordinary cotter-pin 26 to maintain it in position.

Fromthe lower end of the sleeve 16 there may extend a pair of horizontalears 27, and the two may be connected to the upper end of the bell-cranklever 13 by a link 28.

A rock-shaft 29 is located in suitable transversely opposite bearings30, secured to the under side of the burner or framework oftheautomobile, and depending from the rockshaft and moving therewith arerock-arms 31 and 32. A connecting-rod 33 connects the lower end of therock-arm 32 with the corresponding end of the bell-crank 13, and asimilar rod 34 connects the lower end of the rockarm 31 with thecorresponding rock-arm 35,

with the aforesaid rock-arm when the latter moves forward, as shown inFig. 2, and hence the valve 5 in the main gasolene supply closed. Thislatch of course is capable of being sprung to one side by hand, so as torelease the engaged rock-arm when desired.

38 designates a contact-arm, the same beingsenu-fed by a screw 39 toaf'convenien't portion of the framework and insulated therefrom, as at40. The lower end of this arm is outwardly bent, as at 41, to lieimmediately under the lower end of the movable portion carried by thepipe or tube 10, which would be the stem 22, whereby when the sleeve 16is lowered on the pipe a contact with the arm 38 is made.

42 designates in this instance a buzzer, or it may be any form ofaudible alarm, and from the same there leads a connecting-wire orelectrical conductor 43, the opposite end of the conductor beingconnected by the screw rock-arm 35 through the rod 34 and the rockarm31, from the latter to the rock-shaft 29, to the rock-arm 32, fromthence through the connecting-rod 33 to the bell-crank, and through thepipe 10 to the sleeve 16, the plug or cap 19, and tothe stern 22, fromthence to the contact-arm 38 and from the latter to the conductor 43 andback to the battery through the alarm, which will be sounded, and thuswarn the operator of the condition of the boiler. Taking the parts inthe position shown in Fig. 1, we will suppose that the water in theboiler has reached a point below the fusibleplug tube and that the plugbeinilr exposed to the heat ofthe burner has melted and blown out by thepressure of steam. The steam will be conducted immediately through theel bow 9 and pipe 10, where it will contact with the head 23, causingthe latter, with the stein 22 thereof, to be forced downward, carryingwith it the sleeve 16, against the tension of the spring 1'7. This willcause the stern 22 to contact with the contact-arm 38 and sound analarm. 1n .the event the main re is burning it will immediately beautomatically cut off by the valve 5, which will become locked in itsclosed position by the latch 37 and cannot be again turned on until thelatch is disconnected from the rock-arm 31. This locking feature may beomitted; but I prefer to use the same in that in the event theautomobile is left standing unattended and the fusible plug should blowout themain fire will be cut off automatically, and the operator uponreturning to the vehicle will be unable to turn on the main fire andwill necessarily be obliged 4to disconnect the latch 37 from therock-arm 31, in which event he will be apprised of the fact that he hasblown out the lug and should not relight his fire until he llasreplenished the water in the boiler by means of the auxiliary hand-pumpprovided for that purpose. It will be obvious, furthermore, that whenthe head 25 is forced downward the valve-face 47, formed on the underside of the head, will abut against the upper side of the cap or plug19, thus preventing the escape of steam through the opening 21 in saidplug orv cap, so that the pressure of steam is maintained. This willenable the operator to proceed on his journey withoutv the necessity ofremoving the tube and renewing the fusible plug at that time,

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Vpipe for operating or closing the valve o which latter operation he maythus postpone until a more convenient time-as, for instance, when he hasarrived at the end of his journey or at some suitable place. i

It will be observed that when the sleeve descends the bell-crank lever13 will be operated or oscillated and in turn will operate the cut-ofi11, so as to shut off the escape of steam to the sleeve 16, thusallowing the sleeve to retract and the alarm cease. If preferred, Il mayomit this valve and simply mount the bell-crank lever 13 upon a stud andpermit the steam to escape into the sleeve 16, thus keeping up acontinuous alarm. It will be obvious that when the bellcrank lever isoperated, as described, it will through the medium of theJlconnecting-rod 33 swing the rock-arms 31, 32, and 35 forward, thuscutting oli the gasolene-supply at the valve 5 and locking the rock-arm31, so that the main burner cannot be again turned on until the latch 37is disconnected from the rock-arm 31. v

It will be obvious that by removing the bell-crank lever 13 from Athestud 12 the sleeve and tube or pipe 10, carrying the same, may beremoved, with its elbow, from the fusible-plugcarrying tube or sleeve 7and either the plug renewed and the parts vreplaced or a newplug-carrying pipe or tube inserted in its place and the sliding sleeve,together with the parts carried thereby, replaced and the bell-cranklever again mounted on the stud 12.

As is well known the fusible lug seldom for any length of time completey closes the fusible-plug tube or pipe 7, and the result is that thereis always more or less drippingrom the pipe or tube. This dripping isprovided for by reason of the angular-headed valve 23, which by reasonof its shape produces at its four sides clearance-openings, as shown inFig. 4, so that the drip may pass out through the hole 21 in the bottomcap or plug 19.

Certain novel features of construction herein illustrated and described,but not claimed, Jform the subject-matter of a companion pendingdivisional applicationnamely, Serial No. 240,824, iiled January 12,1905.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. The combination with a steam-boiler and its burner, of a fusible plugpipe, a main liquid-fuel-supply pipe having a valve or cut-off, meansadapted to be actuated by the steam-pressure within the f'usiblellkllg te fuel-supply pipe, and an automatic locking device for said valve whenthe same is operated or thrown to a closed position.

2. rifhe combination with a steam-boiler and its burner, of afusible-plu@ pipe, an extension coupled thereto, a s iding sleevemounted on the extension, a main liquidfuel-supply pipe, a valve orcut-off therein, a rock-arm extending Jfrom the stem of the valve, anintermediate rock-shaft, a pair of rock-arms extending from the shaft, arod connecting one of said rock-arms with the rock-arm of the valve,means for actuating the second rock-arm by themovement of the sleeve,and a latch arranged in the path of one of said rock-arms and adapted toenga e the same when the valvein the fuel-supp y pipe is closed and thesleeve actuated.

3. The combination with a steam-boiler and its burner, of a fusible-plupipe, an extension coupled thereto, a siding sleeve mounted on theextension, a main liquidfuel-supply pipe, a valve or cut-off therein, arock-arm extending from the stem of the valve, an intermediaterock-shaft, a pair of rock-arms extending from the shaft, a rodconnecting one of said rock-arms with the rock-arm of the valve, meansfor actuating the second rock-arm by the movement of the sleeve, and alocking deviceadapted to eniglflige and lock one of said rock-arms whenthe el-supply pipe is closed.

4. The combination with a` steam-boiler and its burner; of afusible-plug pipe, an extension connected to the same and terminating atits lower end in an enlarged head, a sleeve mountedto reciprocate uponthe extension and depending below the head, a coiled spring interposedbetween the head Pand up erend of the sleeve and adapted to normal yelevate the latter, a valve at the lower end of the sleeve, a spring fornormally elevating the same from its seat, a fuel-supply pipe, a cut-0Htherein, and means actuated by the movement of the sleeve for operatingsaid cut-oi.

5.. The combination With a steam-boiler and its burner, of afusible-plug pipe connected to the boiler, a sliding element mounted-for reciprocal movement u on and inclosing the fusible-plug pipe, a fue-sup p1y, a cutofi1 therein, and means operated by the reciprocalmovement of said sliding element forA operating the cut-off.

6. The combination with a steam-boiler and its burnerkof a fusible-plugpipe, an extension-pipe coupled thereto and terminating at its lower endin a head, a sliding sleeve mounted on the extension above the head, acoiled sprin inserted between the sleeve and the head, aored cap in thelower end of the sleeve, a stem mounted in the bore and having at itsupper end an angular head and below the same a valve for closing thebore, a spring for normally elevating the head, a bellcrank levermounted on the extension-pipe, arms projecting from the sleeve, aconnecting-rod between one branch of the bell-crank and said arms, amain fuel-supply pipe, a valve therein, an intermediate rock-shaft,rockarms depending therefrom, a connec- IOO tion between one of saidrook-arms and a rook-arm carried by the valve of the fuel-supply pipe,and a connection between the remaining rock-arm and the said bell-cranklever.

7. The combination with a steam-boiler and its burner, of a fusible-plupipe terminating in a stop or head, a siding sleeve mounted on thefusible-plug pipe, a spring for normally pressing the sleeve in adirection contrary to that of the flow of steam when the plug in thefusible-plug pipe is fused, a

CHRISTOPHER G. GILDARD.

Witnesses J. HENRY WELLS, NICHOLAS HATHEWAY, J1'

